atxmega32a4u not enumerating?

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Hi everyone,

 

I've recently created a dev board for an ATXMEGA32a4u. After building the PCB, I cannot get the device to enumerate (I believe that's the right term) or show up as connected to a USB port in USBView.

 

Here is a link to my schematic/board layout screenshots: https://imgur.com/a/oh0Ap

 

Note the LDO is an NCP1117.

 

I've tried a few different things that I've seen on other XMEGA dev boards I've found on here, but nothing has improved my situation:

  • Removing the 22 ohm resistors on the USB lines
  • I added a pull-up line to the reset switch w/ a 10k resistor and without
  • I tried entering bootloader mode by shorting PC3 to ground as per AVR1916

 

I read on one topic on here (cannot find link, sorry) that the 32a4u does not ship with a bootloader, and I'll need to flash one myself to get it to recognize via USB? Which tool will I need to do that?
 

Thanks.

Last Edited: Wed. Nov 29, 2017 - 05:30 AM
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R4 and R5 are unnecessary, but I see you have already tried removing them.

 

The XMEGA range doesn't ship with a bootloader, you need to load your own with a programmer. The best one is the AtmelICE, but Microchip doubled the price so if you just want something basic with no debug capability have a look on eBay.

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mojo-chan wrote:
The XMEGA range doesn't ship with a bootloader
You sure about that for all models? AVR1916 seems to have DFU source for a lot of the Xmega models. Like the AT90USB chips I thought the source was provided to show you what was already pre-loaded into the chips.

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Hmm, well actually I'm not sure... Every one I have ever seen hasn't had the bootloader pre-loaded.

 

I see that even the 16k A4U range has a 4k boot section... I'm guessing they couldn't fit DFU/FLIP into 2k.

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Is there a cheaper alternative to the AtmelICE for flashing a bootloader? I'm comfortable flashing using avr/dfu/etc via USB once the bootloader is flashed.

What about an AVRISP MkII clone? They're about ~$25 on eBay.

Last Edited: Wed. Nov 29, 2017 - 11:51 AM
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The AVRISP mkII clone will work fine. Genuine ones go for next to nothing occasionally: https://www.ebay.co.uk/itm/AVRIS...

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mojo-chan wrote:

The AVRISP mkII clone will work fine. Genuine ones go for next to nothing occasionally: https://www.ebay.co.uk/itm/AVRIS...

 

Thanks, I wish I could get that one bc it's super cheap but they won't ship to the US lol. I'll keep looking though.

 

Edit: I have a UK-based buddy bidding on it now to proxy for me. Wish us luck!

 

Edit 2: He won the auction, genuine AVRISP MKII shipped to me for $35ish isn't bad at all.. Also, just realized ALLPCB has a $5 "small board" offer with FREE express DHL shipping. Looks like I'm making a Rev 2 of my board.

Last Edited: Wed. Nov 29, 2017 - 12:40 PM